This invention relates to filter apparatus of the type having elongate, tubular fabric filter bags for filtering and collecting particulate material on the exterior thereof and which are cleaned periodically by a reverse flow of air therethrough. In some instances, such reverse flow of air enters the the filter bags by way of a plenum common to a respective group of the filter bags. In other instances, a so-called "pulse jet" technique of cleaning the filter bags has been employed in which high energy jets of reverse flowing air are directed into and through tubular venturis and thence through respective filter bags so that the reverse air flow expands suddenly upon entering the filter bags for shaking the same to aid in dislodging the collected particulate material therefrom.
While the pulse jet technique may have improved the cleaning of the filter bags to some degree, it has been found that much improved results have been achieved in the cleaning of such filter bags by combining an air diffuser, as set forth in my said copending application, with the aforementioned pulse jet cleaning technique. Accordingly, it is a primary object of this invention to provide a filter apparatus of the type described wherein an air diffuser tube generally of the type set forth in said copending application is combined with each venturi tube within the respective cage and filter bag.
It is a more specific object to provide a bag-type filter apparatus with a hollow perforate open-ended air diffuser means or perforated tube which is communicatively connected to, supported by and extends from a tubular venturi and within a tubular cage on which each respective tubular filter bag is supported, and wherein the air diffuser means or tube is thus positioned in each cage for receiving a reverse flowing high energy jet of air via the respective venturi for diffusing and distributing the air throughout the filter bag when a periodic reverse flow of a jet of air is directed into the respective filter bag so as to more effectively clean the filter bag while also reducing excessive flexing of the filter bag and abrasive wear thereof to thereby provide a substantial increase in the efficiency of the filter apparatus and a significant increase in the life of the filter bag.